The invention is an optical polarization separator and its use in a display system. In particular, the device according to the invention separates the two polarizations in an unpolarized light beam and, in a preferred embodiment, transmits them to an electro-optical display device such as a liquid crystal screen.
The principle of retrieving the unused source polarization, separating it, rotating it and then adding it to the direct polarization has been described in many patents and publications. The polarization is generally separated by reflection/transmission on a multilayer dielectric (using the Brewster angle) or by Bragg reflection of a circularly polarized component on a chiral structure. However, these separators are limited by the acceptable aperture and wavelength.
Rotation for recombination is generally done by a set of mirrors or a twisted nematic structure. Recombination generally requires a large number of dioptric systems and the efficiency is far from the theoretical value of 2. In addition, the polarization quality is inadequate and a last, conventional polarizer must be introduced to obtain satisfactory image contrast.
Moreover, systems known to the prior art are bulky and heavy. The device according to the invention is smaller and lighter due to the small number of efficient dioptric systems it requires.